no, these are very much real. they may not be the in-game ones, but chris senn himself made these models.http://vignette2.wikia.nocookie.net/sonic/images/0/07/Sonic_downloads.jpg/revision/latest/scale-to-width-down/640?cb=20111125161325

This is fake asf. literally just someone trying to get anonymous attention for they're garbage model skills. This doesn't resemble literally anything we've ever seen from the game ever. https://media.sonicscanf.org//gallery/sonic-the-hedgehog/sonic-x-treme.png https://i.ytimg.com/vi/2z45v3s_CuA/hqdefault.jpg https://www.spriters-resource.com/resources/sheet_icons/26/28326.png I mean just look at the OFFICIAL SPRITES, it clearly wasn't the models used for the sprites and they're has never been any reference to tails being in the game.

We'll probably never see the ones from Rare's Donkey Kong games. They were stored on floppy disks, and when they were doing the GBA remakes, they wanted to use the original models...only to discover that most of the floppies were missing, and of the few they had left, the data was difficult to decrypt on modern computers. Oh, well...